1. Technical Field
The present invention generally relates to load transport vehicles, and a method for loading and unloading same. More particularly, the present invention relates to a tractor and an enclosed semi-trailer which can be loaded from a front end and unloaded from a rear end or vice versa, and method of loading and unloading same having first-in/first-out load/unload capabilities.
2. Discussion
An efficient and cost saving transportation system is essential to the operation of modern industrial societies. Through the centuries, the methods of transporting goods and materials from one location to a distant location have evolved to today where millions of tons of goods and materials are carried upon highways by tractor and semi-trailer rigs which have become familiar sights on the world's highways and byways.
A conventional tractor and semi-trailer rig is so named because the trailer relies on the tractor to carry part of its weight. A conventional tractor and enclosed semi-trailer van rig has standard rear loading doors which require the loading/unloading of the tractor and semi-trailer rig in a last-in/first-out sequence, that is, the cargo which is loaded last is the cargo that is unloaded first. This last-in/first-out sequence or loading/unloading means that for specific cargo which is to be unloaded first, that specific cargo must be loaded last. Manufacturing companies have revised their shipping and receiving procedures to minimize their inventory costs and have gone to some type of a just-in-time procedure. When the product being received is designed specifically for a particular application, the just-in-time/in-line-sequencing procedure is utilized. When using this just-in-time/in-line-sequencing procedure, it is necessary to use assemblies, and thus unload these assemblies, in the order that they were manufactured. For the manufacturer or shipper, this requires a rather substantial shipping staging area or loading dock in order to temporarily store the assemblies that were manufactured first. Storage for the first manufactured assemblies is required until racks containing the final group of manufactured assemblies to be shipped are filled and loaded on the tractor and semi-trailer rig first thus allowing the first manufactured assemblies to be loaded last. This loading/unloading procedure is required for a just-in-time/in-line-sequencing requirement. Such a loading/unloading method is inefficient and unnecessarily time consuming due to the multiple handling and movement of the manufactured assemblies. It is also space consuming and promotes out of sequence loading errors.
Some conventional tractor and semi-trailer rigs include loading doors located on the side. Such full length side loaded trailers require loading from road level as opposed to loading from a standard loading dock height, or if loaded from a loading dock, they require a rather large loading dock area. The space constraints associated with loading a full length side loaded tractor and semi-trailer rig also make it difficult to protect the workers and the forklift operators from inclement weather conditions.
A conventional tractor and semi-trailer rig is rather large and cumbersome. Visibility for the driver is often limited. The maneuverability of such large rigs into a small loading dock area where visibility is often limited is time consuming, tedious and difficult. Even drivers having a vast amount of experience and skill exhibit driver error from time to time under these difficult conditions.
Therefore, numerous disadvantages currently exist in load transport vehicles, and in the methods for loading and unloading same. Continued development in the transportation industry has been directed towards simplifying the loading/unloading of these vehicles and eliminating the above described disadvantages.